Sexual harassment is a type of harassment involving the use of explicit or implicit sexual overtones, including the unwelcome and inappropriate promises of rewards in exchange for sexual favors. Sexual harassment includes a range of actions from verbal transgressions to sexual abuse or assault. Harassment can occur in many different social settings such as the workplace, the home, school, or religious institutions. Harassers or victims may be of any sex or gender.

In modern legal contexts, sexual harassment is illegal. Laws surrounding sexual harassment generally do not prohibit simple teasing, offhand comments, or minor isolated incidents—that is due to the fact that they do not impose a "general civility code". In the workplace, harassment may be considered illegal when it is frequent or severe thereby creating a hostile or offensive work environment or when it results in an adverse employment decision (such as the victim's demotion, firing or quitting). The legal and social understanding of sexual harassment, however, varies by culture.

Sexual harassment by an employer is a form of illegal employment discrimination. For many businesses or organizations, preventing sexual harassment and defending employees from sexual harassment charges have become key goals of legal decision-making.